Autogenous smelting of lead in a top blown rotary converter

Abstract

Processes are provided for the autogenous production of crude lead from sulphidic lead concentrates or complex sulphide materials containing lead. The processes are carried out in a rotary converter with the rotation axis inclined to the plane of the vertical. In the process the sulphidic materials are smelted and reduced while the converter is rotated.

I claim: 
     
       1. The method of autogenous production of crude lead from materials containing lead sulfide comprising the steps of rotating at 10-60 r.p.m. a pre-heated top blown rotary converter on an axis inclined to the horizontal plane at a speed of 0.5-7 m/s measured at the inner periphery of the cylindrical part of the converter,   charging the lead sulfide containing materials into said rotating converter and simultaneously,   introducing oxygen or oxygen-enriched air into said furnace so that the sulphur in the charge is combusted and the heat thereby obtained is caused to generate a smelt of lead and a lead containing slag, said smelt of lead and said lead containing slag by means of the frictional force induced by the rotational speed being lifted up along said inner periphery of the converter to a level at which smelt falls down as finely-divided drops of liquid,   treating said smelt of lead and said lead containing slag with reducing agents so that lead content of said slag is decreased not to exceed 10%, and thereafter   tapping slag and crude lead from the furnace; said crude lead having a sulfur content not exceeding 2%.   
     
     
       2. The method of claim 1, wherein oxygen or oxygen-enriched air is further introduced before tapping, but after lead sulfide charging is terminated, whereby the sulfide content in the smelt is further decreased. 
     
     
       3. The method according to claim 1, in which the quantity in mol of oxygen supplied relative to the quantity in mol of lead sulfide is between 0.8 and 1.4. 
     
     
       4. The method according to claim 3, in which the ratio is 1.0-1.2. 
     
     
       5. The method according to claim 1, in which the oxygen content of the gas supplied is greater than 40%. 
     
     
       6. The method according to claim 1, in which dust obtained in the process is returned to the converter. 
     
     
       7. The method of claim 1 wherein the reducing agents are selected from the group consisting of metal sulfides and carbon-containing fuels. 
     
     
       8. The method of claim 7 wherein the carbon-containing fuel is coke. 
     
     
       9. The method according to claim 1, in which the top blown rotary converter is pre-heated to a temperature over 800° C before charging said lead sulfide-containing materials. 
     
     
       10. The method according to claim 1, in which the temperature during the smelting is maintained between 900° and 1200° C. 
     
     
       11. The method of claim 1, wherein said speed is 2-5 m/s.